On the eastern side of the mud pile, crews have been getting four to six "hits" on human remains a day, though some of those are not easily identifiable and may not have been added to the official death toll yet.

After dogs and search teams clear one section of the site and are certain there's nothing more to be found there, they use excavators to bring debris and mud from another area there.

Finding enough free space has been a challenge, said Steve Harris, division supervisor for the state incident team overseeing the east side of the mudpile.

"At one point we may actually do a bit of trucking of the material to an area where it’s secure," Harris said.

It's unclear what the long-term plan is for the mud — enough to cover hundreds of football fields.

"It can be moved, but it's too soon to tell what will happen," said Bart Treece, a spokesman for Washington State Department of Transportation.

Much of the muck may be toxic due to the debris containing household chemicals and flammable gasses from wrecked homes.

Authorities have brought haz-mat teams to the scenes and set up decontamination facilities so "we don't bring any bad stuff back," Harris said.